fix(auth): resolve Vercel 504 timeout by optimizing middleware queries

[EmiyaKiritsugu3]

Description

This PR resolves the MIDDLEWARE_INVOCATION_TIMEOUT (504 Gateway Timeout) on Vercel production by optimizing the auth middleware logic.

🔍 RCA

The middleware was performing up to 3 sequential Supabase network calls per protected request. Given the cross-region latency between Vercel Edge and the Supabase DB (Brazil), this often exceeded the Edge Runtime execution limit.

⚡ Fix

Consolidated the employee existence check and role fetching into a single query.

• Reduced network round-trips by 50% for restricted routes.
• Eliminated redundant select('id') query.

Type of Change

• perf — Performance improvement
• fix — Bug fix

Related Documents

• Incident Log: docs/process/sentinel-log.md

Checklist

• npm run typecheck — zero errors
• npm run lint — zero errors
• npm run format:check — no formatting issues
• npm test src/lib/auth.test.ts — all tests pass
• Documentation updated (Sentinel Log)

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Project	Deployment	Actions	Updated (UTC)
smartmanagementsystem	Ready	Preview, Comment	May 6, 2026 1:48pm

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Run ID: 1f147102-e209-4f4d-a529-02d4b7a9d53f

📥 Commits

Reviewing files that changed from the base of the PR and between 25d7f0f and b0df206.

📒 Files selected for processing (2)

• docs/process/sentinel-log.md
• src/utils/supabase/middleware.ts

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/middleware-timeout

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